package demo3Computer;

public class Computer {

    public void open(){
        System.out.println("开机");
    }





    public void close(){
        System.out.println("关机");
    }

    public void useUsbDevice(USB usb){
        usb.openDevice();

        if(usb instanceof Mouse){
            Mouse mouse=(Mouse) usb;
            //向下转型调用click方法
            mouse.click();
        }else{
            KeyBoard keyBoard=(KeyBoard) usb;
            //向下转型调用input方法
            keyBoard.input();
        }

        usb.closeDevice();
    }
}
